(1) Field of the Invention
The invention relates to a valve for controlling or preventing flow of a flowing medium.
(2) Description of the Prior Art
German Utility Model 72 31 278 describes a known such valve including means for controllably adjusting the separation between a housing seat and a movable shut-off element, full closure of the valve by the shut-off element being effected by a separate diaphragm drive being superimposable on the control motion.
However, when such known valves have large dimensions and are to be employed to control the flow of high temperature fluids, the diaphragms need to be made extraordinarily large in order to withstand the high loads occuring. Particularly at temperatures which call for the use of a metallic diaphragm the deformation of the diaphragm must still only be minimal.